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Surface and Semiconductor Physics

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Introduction

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The research within the division concerns two main fields. First, basic studies are made of the electronic and atomic structure of semiconductor surfaces, either clean or with well characterized overlayers. Second, there are studies, development and application of silicon-based molecular beam epitaxy, which is a crystal growth technique to produce advanced semiconductor devices.

We are extensive users of the synchrotron radiation facility MAX-lab in Lund and over the years we have built up experimental equipment at two different beam lines. One of us, Prof. Roger Uhrberg, is working actively with the angle-resolved photoelectron spectroscopy (ARPES) beam line, which is one of the first seven to be built at MAX IV. The beam line, which will be located at the 1.5 GeV ring, has received a funding of 70.2 MSEK.

As an example, two-dimensional Sn/Ag surface alloy on the Ge(111) and Si(111) surfaces are given in the following:

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Fig. 1. a) and b) show filled and empty state STM images of the Sn/Ag/Ge(111)3x3 surface alloy, respectively. c) Fermi surface of the surface alloy. d) and e) Surface band dispersions along the symmetry direction in b). The Fermi surface is formed by the uppermost, steeply dispersing, bands.

 

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Fig. 2. a) and b) show filled and empty state STM images of the Sn/Ag/Si(111)2x2 surface alloy, respectively. c) Free electron like surface band, S1. d) The two constant energy contours around every K-point reveal the existence of two enantiomorphous structures.

 

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Responsible for this page: Hafiz Muhammad Sohail
Last updated:09/20/13